This is a world called "Meteor Continent". Thousands of years ago, meteorites fell from the sky, bringing strange stones containing "original power". Human beings awakened to different abilities: warriors tempered their bodies, mages controlled elements, assassins concealed in shadows, doctors healed vitality... Summoners were once the most glorious profession - they could form contracts with heaven and earth spiritual beings and ancient souls, and fight side by side. However, after a "Spirit Summoning Catastrophe", the spiritual creatures contracted by Summoners collectively lost control, causing the destruction of all life on the mainland. The profession has since been regarded as a taboo. The survivors either hide among the people or are hunted down by major forces, and the inheritance is almost cut off.
